30-12-2020, 10:50 AM
Never tried a back to back with a 9E Bob,but against a modified late Ruby head on a dyno gave 3 bhp I am told.This from someone who has had several Ricardo pattern heads.I don't think he would have bought more than one if they didn't work.
I don't know of another A7 head with plugs fitted on the inlet side but Ford ,Harley Davidson ,Douglas,and Jowett did.
I did try putting 10mm plugs (Racing plugs) down the priming cock holes (On the inlet side) in an early head,It did 1500 miles on an oily engine and the plugs were clean still when the head was removed,and they had never been cleaned.
This head was disappointing considering it was skimmed to the max for a std lift cam and the old plug holes were plugged and profiled inside the combustion chamber.Put this down to poor transfer flow to the cylinders.
I don't know of another A7 head with plugs fitted on the inlet side but Ford ,Harley Davidson ,Douglas,and Jowett did.
I did try putting 10mm plugs (Racing plugs) down the priming cock holes (On the inlet side) in an early head,It did 1500 miles on an oily engine and the plugs were clean still when the head was removed,and they had never been cleaned.
This head was disappointing considering it was skimmed to the max for a std lift cam and the old plug holes were plugged and profiled inside the combustion chamber.Put this down to poor transfer flow to the cylinders.